World: r4wp

f: does [2]
;on R3
>> reduce/only [a f] none
== [1 make function! [[][2]]]
;On R2
>> reduce/only [a f] none
** Script Error: Invalid argument: f

Is it a bug on R2?

a: 1 ;for sure..

Looks like a bug in R2 to me.


It's interesting, that the word for the function is reduced to the 
function, but not evaluated. An alternative could be, that the word 
isn't touched, if it represents a function. I'm not familar with 
what practical challenges, that lead to this refinement for REDUCE. 
I've never used it myself.

An alternative could be, that the word isn't touched
You can do that like
>> reduce/only [a f] [ f ] ;this doesn't touch to F
== [1 f ]

But this is not only for functions of course.